The evolution of the shape of composite dowels

Wojciech Lorenc; Günter Seidl; Jacques Berthellemy

doi:10.2478/sgem-2022-0021

Figure 1

Steel–concrete hybrid beams of innovative composite bridge constructed using composite dowels in Poland, 2016.

Figure 2

Continuous shear connectors [13]: a) Perfobond, b) kombi, and c) composite dowels using puzzle shapes that have been tested in the context of [7] project and d) additional shapes of shear connectors studied by different researchers [44].

Figure 3

Model of the “PreCo-Beam” girder (picture and model by SSF).

Figure 4

Shapes of composite dowels a) fin SA, b) puzzle PZ, c) clothoidal CL, and d) modified clothoidal MCL.

Figure 5

Shear connection for the viaduct in Pöcking [50] with puzzle-shaped dowels.

Figure 6

Composite girders of the viaduct in Pöcking [50] with puzzle-shaped dowels.

Figure 7

Steel part (“external reinforcement”) of the girders for the pedestrian bridge in Przemyśl, Poland (picture from the proposal of the PreCo-Beam project [7]).

Figure 8

Steel dowels (SA shape according to [7]) used in the girders for the pedestrian bridge in Przemyśl, Poland (picture from the proposal of the PreCo-Beam project [7]).

Figure 9

Fin-shaped dowel [30].

Figure 10

Modification of the SA shape (elimination of sharp notch) [7].

Figure 11

Modified SA shape (without the sharp notch) used in the Vigaun Bridge [7].

Figure 12

Illustration of the FE study of the push-out test [13].

Figure 13

Assumptions for the 1D1 model used for the purposes of [7].

Figure 14

Modifications of the concrete material law (uniaxial strain–stress curves, concrete-damaged plasticity model) for purposes of different numerical simulations.

Figure 15

The 1D1 model is one of the first models prepared for the purposes of the PreCo-Beam project [7]. The displacement layout of the model with a maximum value (red) of 3 mm results in force displacement for particular material curves according to Fig. 14.

Figure 16

Shear failure mechanism of concrete dowel by Seidl [30] (last two stages of drawing from the final report [7]: III – the concrete wedge penetrates the concrete dowel and IV – the fully developed shear interfaces and mobilized the reinforcement bar).

Figure 17

Comparison of the numerical results for the model according to Fig. 12 with the experimental results of the push-out tests according to [51,30].

Figure 18

Steel shapes studied by SETRA at early stages of project [7] presenting yielding of plane models (reduced stress layouts): a) fin shape, b) early version of puzzle shape, c) one of the shapes that has been studied but was never used for testing.

Figure 19

Plastic deformations of steel dowels in the region of the sharp notch in the SA shape (push-out specimen [30]).

Figure 20

Numerical model of the so-called “crestbond” connector [10] studied for purposes of [7]: a) the geometry of solid model using ¼ symmetry, b) the net of finite elements used in the model for nonlinear analysis.

Figure 21

Topology of the shapes of steel dowels considered for the purposes of [7].

Figure 22

1D1 models (geometry of the concrete part, steel part, and reduced stress layout, providing a general view of the yielded steel part) studied for the purposes of [7]: a) PZ shape (also called SP), b) SA shape, and c) SV shape.

Figure 23

Results of 1D1 models (PZ, SA, and SN shapes) for particular specifications of the FE model: force–displacement curve, material curve for concrete TcCd according to Fig. 14 and isotropic hardening for steel [1]; time of 1 s for the explicit procedure [1] and approximately 0.01 m size of the finite elements (solid elements, reduced integration) [1].

Figure 24

Study of the SN shape: a) the basic idea of cutting, b) modification of cutting to achieve a stronger steel part compared to the concrete part, c) reduced stress layout for the chosen geometry of the SN shape (short steel dowel) with steel web thickness equal to 10 mm (steel failure), and d) reduced stress layout for the chosen geometry of the SN shape (long steel dowel) with steel web thickness equal to 30 mm (concrete failure).

Figure 25

Comparative study of shapes for particular ratios (force–displacement curve, 1D1 model, linear concrete material and nonlinear steel material): typical curve presenting steel failure.

Figure 26

Results of shape optimization presenting the force per unit length versus shape ratio (1D1 model, linear concrete material and linear steel material; RI represents reduced integration in finite elements [1]).

Figure 27

Results of tests for different sizes of dowel [5] (later [13,31]).

Figure 28

Effect of the size of steel dowels: illustration of ductility δ defined by the angle and height of the dowel [5] (later [13,31]).

Figure 29

Clothoidal shape (CL) by Berthellemy: a) idea for geometry and cutting line, b) structural solution for an orthotropic deck as the basis for the geometry and dimensions.

Figure 30

Results of the optimization of the CL shape versus the SN shape, presenting the force per unit length versus shape ratio (1D1 model, linear concrete material and linear steel material; RI represents reduced integration in finite elements [1] and C1 and C2 represent different contact interactions).

Figure 31

General view of the CL shape tested in the PreCo-Beam project [7] with a height of 100 mm and spacing between dowels equal to 300 mm (specific nomenclature used for composite dowels is given).

Figure 32

“Perfobond” by Fritz Leonhardt (a) and system by Pierre Trouillet (b).

Figure 33

Girders of bridges with continuous shear connection based on friction: a) main girders with shear connection plates, b) transversal tendons, and c) beam specimen for tests (tests achieved in 1965).

Figure 34

Bridges described in OTUA bulletin n°6 by Henri Grelu: a) l’Oise A15 (1966), b) Cergy l’Hautil RD203 (1969), and c) Conflans RN 184 (1973).

Figure 35

Pictures of the A15 motorway bridge over River Oise in 2008: good structural condition (slab condition of the second bridge on the left – built more recently without tendons – is not so good).

Figure 36

Bottom view of “Wierna Rzeka” bridge.

Figure 37

First railway bridge with composite dowel shear connection: a) cross section; b) fabrication of a clothoidal-shaped dowel cutting line substituting the cutting line presented in Fig. 29a; c) basic reinforcement forming composite dowels; and d) a prefabricated composite beam girder lifted by a crane [6].